Decision Optimization

 View Only
  • 1.  reduced costs at root node relazation

    Posted Fri September 08, 2023 11:23 AM
    Edited by Rory Keeley Fri September 15, 2023 04:29 AM

    Hi everyone,

    I am trying to retrieve the solution of root node relaxation using callbacks in cplex concert c++. I am particularly interested in getting the reduced costs associated with each decision variable. Unfortunately, I could not find a way to retrieve them, and it seems that I can not use the getReducedCost() method inside a callback class. Does someone has a better idea how to get them ?

    Below a snap of my callback procedure.

    Thanks a lot !

    ILOUSERCUTCALLBACK1(rootNode, proximitySearch&, model)
    {
    int i, j, t;
    const auto K = model.K;
    const auto N = model.N;
    const auto T = model.T;
    auto& y = model.y;
    auto& yy = model.yy;
    auto& z = model.z;
    auto& zz = model.zz;
    if (getNnodes() == 0) {
    cout << "root node relaxation accessed" << endl;
    cout << "BandC Obj: " << getObjValue();
    cout << " BestObj: " << getBestObjValue();
    cout << " IncumbtObj: " << getIncumbentObjValue() << endl;
    cout << " pseudocost: " << getDownPseudoCost(z[1][1][1]); cin.get();
    for (i = 0; i < N; i++) {
    for (t = 1; t <= T; t++)
    {
    for (auto k = 1; k <= K; k++)
    {
    model.z_root[i][t][k] = getValue(z[i][t][k]); double val = model.z_root[i][t][k]; 
    for (j = 0; j < N; j++)
    {
    if (i != j) model.y_root[i][j][t][k] = getValue(y[i][j][t][k]);
    }
    }
    }
    }
    getReducedCosts(model.y, yy);  -> this does not work
     
    }
    }


  • 2.  RE: reduced costs at root node relazation

    Posted Fri September 15, 2023 05:12 AM

    Can someone help ? or provide some useful references ?

    Thanks!



    ------------------------------
    Mohamed Ben Ahmed
    ------------------------------



  • 3.  RE: reduced costs at root node relazation

    IBM Champion
    Posted Thu September 21, 2023 02:01 PM

    You might want to take a look at Daniel's second answer in this thread.



    ------------------------------
    Paul Rubin
    Professor Emeritus
    Michigan State University
    ------------------------------



  • 4.  RE: reduced costs at root node relazation

    Posted Wed September 27, 2023 04:02 AM

    Thank you Paul ! very helpful !



    ------------------------------
    Mohamed Ben Ahmed
    ------------------------------